1. Field of the Invention
The present invention generally relates to a semiconductor module, and more particularly, the present invention relates to a pattern shape for a contacting portion formed on a printed wiring board.
This application is a counterpart of Japanese application Serial Number 096414/1999, filed Apr. 2, 1999, the subject matter of which is incorporated herein by reference.
2. Description of the Related Art
FIG. 3 is a schematic diagram showing a semiconductor module of a conventional art.
As shown in FIG. 3, a plurality of surface mounting type semiconductor packages 101 (e.g. T-SOP (Thin-small Outline Package) is mounted on a memory module. Concretely, for forming an electric circuit, the plurality of surface mounting type semiconductor packages 101 are formed on a printed wiring board 102 (e.g. a glass epoxy resin substrate, or a ceramic substrate). The printed wiring board 102 has a structure formed of a conductive pattern on an insulating material. For electrically connecting a module product with an external device (e.g. a personal computer), a plurality of external terminals 103 is formed on the printed wiring board 102.
FIG. 4 is a cross-sectional view taken in the direction of the arrows substantially along the line axe2x80x94a of FIG. 3.
As shown in FIG. 4, the plurality of surface mounting type semiconductor packages 101 is made up of a semiconductor device 201 having an integrated circuit, a lead 2020 for transferring an electrical signal of the semiconductor device 201 to an external portion, a wiring 203 (e.g. the wiring made of a gold or aluminum) for transferring an electrical signal of the semiconductor device 201 to the lead 202, a resin 204 (e.g. an epoxy resin, a silicon resin) for protecting the semiconductor device 201 and the wiring 203 from an external force, a printed wiring board 205 (e.g. a glass epoxy substrate, a ceramic substrate) formed of a conductive pattern, a pad 206 for transferring an electrical signal of the semiconductor device 201 formed on the printed wiring board 205 to the external portion, a conductive material 3.g. a solder, a conductive resin, an Ag paste) electrically connecting the lead 202 with the pad 206. The plurality of surface mounting type semiconductor packages 101 constructed as mentioned above is mounted on an upper surface and a lower surface of the printed wiring board 205.
FIG. 5 is an enlarged plane view of b portion in FIG. 3. As shown in FIG. 5, a pad 302 formed on a printed wiring board 301 has a width wider than a lead 304.
FIG. 6 is a cross-sectional view taken in the direction of the arrows substantially along the line cxe2x80x94c of FIG. 3.
As shown in FIG. 6, a lead 403 for the plurality of surface mounting type semiconductor packages 101 is electrically connected to a pad 402 formed on a printed wiring board 401 via a conductive material. The pad 402 is set to a width wider than a lead 403.
In the conventional art, it is desired to avoid inferior connections caused by cracks between the lead and the pad.
An object of the present invention is to provide a semiconductor module that can avoid inferior connections caused by cracks between the lead and the pad.
According to one aspect of the present invention, for achieving the above object, there is provided a semiconductor module comprising a chip formed with an integrated circuit, a first external connecting terminal electrically connected to the integrated circuit, a printed wiring board having a second external connecting terminal; and a conductive material electrically connecting the first external connecting terminal with the second external connecting terminal, wherein the conductive material is formed so as to cover a sidewall of the second external connecting terminal.